The digital vigilante groups Anonymous and LulzSec, it seems, plan to teach News Corp. a thing or two about hacking.

Just a day after the arrest of Rebekah Brooks, the chief executive of New Corp.'s British subsidiary and editor of its The Sun newspaper for phone hacking charges, the hacker groups took credit Monday for defacing the paper's website to redirect to a fake homepage (archived here) that claimed its owner, News Corp. chief executive Rupert Murdoch, had died of a drug overdose.

Worse may be ahead for the The Sun than mere graffiti: A hacker who goes by the handle Sabu claims that the hacker groups had also accessed The Sun's and defunct sister paper News Of The World's emails, and may release them in coming days. "Sun/News of the world OWNED," he writes. "We're sitting on their emails. Press release tomorrow."

Sabu and other Anonymous-related twitter feeds followed by twittering email addresses and passwords for Rebekah Brooks and Bill Akass, an editor who has held positions at The Sun and News of the World, and Danny Rogers, currently online editor at The Sun.

"We have owned Sun/News of the World," added a tweet from LulzSec, the hacker group that went on a hacking spree targeting the CIA, Sony and PBS earlier this year only to supposedly disband last month. "That story is simply phase 1 - expect the lulz to flow in coming days."

Update, 7pm Monday: The hackers also claimed to have hacked the website of News International, altering a statement in response to the breach. As of 7pm Monday, however, the site was down.

Update #2, 7:35pm Monday: They've also taken down the website of the News Corp.-owned Times of London.

Update #3, 8:10pm Monday: Now all websites for News International, the British arm of News Corp, are down.

In another message, Sabu seemed to dedicate the attack to Sean Hoare, a former entertainment reporter for the News of the World who acted as a whistleblower in the paper's hacking scandal and was found dead Monday without explanation. "RIP Sean Hoare, a pioneer of #hackgateSean Hoare, a pioneer of #hackgate," Sabu wrote.

A cartoon included on the parody of The Sun's homepage included references to accessing the site through a "buggy Web app" that ran software and hardware, ironically, from Oracle-owned Sun Microsystems.

The hacker Sabu has previously been tied to both LulzSec and an Anonymous operation that spilled 71,000 emails from the security firm HBGary Federal, including a proposal that offered methods for cyberattacks and misinformation campaigns attacking WikiLeaks and its supporters as well as grassroots opponents of the U.S. Chamber of Commerce. In the ensuing scandal, HBGary Federal chief executive Aaron Barr resigned from the company.

Questions are still swirling around News Corp. executives' involvement in voicemail-hacking and police bribery at News of the World, which have already led to the resignation of Rebekah Brooks prior to her arrest. If the internal communications of the paper or its fellow News Corp. tabloid The Sun are leaked as thoroughly as HBGary's, expect the scandal to spill out even further.

Correction: Although both LulzSec (active again after seeming to call it quits three weeks ago) and Anonymous hackers seem to have played a part in this hacking attack, LulzSec has made clear in its Twitter feed that it took the lead role, and Anonymous hasn't contradicted this account. The two groups aren't quite distinct, as I've written. But the original headline for this story stated that Anonymous had hacked the Sun, and I've changed it to focus on LulzSec instead.